Leading business figures and politicians have called for an urgent review of a contentious levy in Northern Ireland after the Irish government said it was scrapping air tax.
In his Budget, the Republic's Finance Minister Michael Noonan said a €3 (£2.50) passenger surcharge on short and long-haul flights will be cut to zero from April 1, 2014.
That compares to the UK's air passenger duty (APD) of £13 for every passenger travelling in economy class on flights of less than 2,000 miles in length.
Those travelling in economy on flights of 4,001 to 6,000 miles pay APD to the tune of £83, while each passenger is charged £94 for economy class on flights of more than 6,000 miles.
Meanwhile, those flying in non-economy seats pay rates that are exactly double what economy passengers pay – for example, the non-economy rate on flights of up to 2,000 miles is £26, while that figure leaps to £188 on journeys above 6,000 miles.
APD on long-haul flights is a devolved matter and Stormont has already abolished air passenger duty in this regard.
But Northern Ireland Finance Minister Simon Hamilton has said it would be too expensive for Stormont to take steps to entirely devolve APD. "The cost to the Northern Ireland block grant and other public services would be significant – between £60-£90m a year," he said.
East Belfast MP Naomi Long said the decision to abolish the levy in Ireland means Northern Ireland must follow suit. She said: "The differential in duty charged on flights between north and south places our airports at a competitive disadvantage."
A spokeswoman for BIA – where United Airlines operates our only international air route from Belfast to Newark/New York – said: "Any tax which makes our gateways less attractive than those across the border is retrograde."